Elevator system



Patented May 17, 1938 UNITED STATES PATENT OFFICE Lll'lll ELEVATOR SYSTEM Danilo Santini, cum, 111., alsignor a Westinghouse Electric Elevator Company, Chicago,

My invention relates to'elevator system and more particularly to means for operating the elevator brake when the car is decelerating to a stop and when the car is releveling at a floor.

One object of my invention is to provide, during the leveling of the car at a floor, means for preventing any undue downward movement of the car before the leveling means operates to bring it back to the floor level.

Another object is to so control the operation of the brake that it will be only partially rewhile a stop is being made, so that suflicient force will be applied by the brake to hold the load.

g and yet the brake will not be applied strong enough to prevent the hoisting motor from leveling the car back to the floor.

Another object is to provide for so controlling the elevator motor that it will receive suillcient 341 additional power during a leveling operation with the brake partially applied to cause the motor to overcome the extra friction caused by the partial application of the brake.

A further object is to provide for applying the v-, elevator brake softly and accurately at the last stage of the deceleration of the car to a stop at a floor landing.

A further object'is to provide for so controlling leveling operations.

Broadly, the means for accomplishing these and other objects includes control means for only partially releasing the brake during a releveling operation and at the same time giving the elevator motor additional power so that it will overcome the extra friction caused by the partial application of the brake while the releveling operation is being eflected. In the pre- 31 v'ious art, when the car overran its floor or slipped beyond its floor by reason of a heavy load stretching its cables, the car'would slide an additional distance after the brake was fully released and before the hoisting motor could take hold. The provision of only partially releasing the brake ,through the partially released brake while releveling, prevents the car from sliding that additional distance.

The invention also includes means for varying the excitation of the brake magnet during the latter stages of deceleration of the car to a complete stop at a floor so that the brake may be applied softly and accurately when the car reaches the final stopping point.

leased when thecar moves beyond the floor level the brake as to prevent the car from moving. 7 away from the floor an excessive amount during and giving the motor additional power to pull- Ill., a corporation of numb Application October 23, 1036, Serial No. 107,184

10 Claims. (Cl. lit-152) l'br a better understanding of the invention, reference may be had to the accompanying drawing, in which:

l"igure l is a diagrammatic representation of an elevator system embodying my invention and what is known as the "straight line" style; and

l"lg.'1A is a representation of the relays included in Fig. 1.

The illustration of the relays in Fig. 1A shows them with their coils and contact members dis- 10 posed in horizontal alignment with their positions in the straight-line circuits of Fig. 1 so that the reader may readily determine the identity of any relay, the number and kind of its contact members and the position or its coil and contact members in the straight-line circuit.

Referring more particularly to the drawing, an elevator car C is illustrated as suitably sus pended in the hatchway (not shown) by a cable H which passes over ahoisting drum I! to a suitable counterweight CW.

The hoisting drum I2 is disposed on the shaft ll driven by a power means including an elevator motor ll having an armature ISA and a separately excited shunt field winding I5F.

The power means also includes a variable voltage system of control for operating the elevator motor wherein the armature of the elevator motor is connected in loop circuit with the armature GA of a generator G. The generator is provided with a series field winding GSF and a separately excited field winding GF. The armature of the generator may be driven by any suitable driving motor (not shown).

The direction of the excitation current for the 5 field winding G! of the generator may be suitably controlled by means of an up directon switch U and a down direction switch D. The value oi the current may be controlled by a pair of resistors RI and R! which may be controlled through an intermediate speed relay.I and a high speed relay V.

A car switch CS is provided in the car for controlling the up and down direction switches U and D in operating the elevator motor to start and stop the car.

An automatic leveling system is provided for causing the car to level itself with the floor if it over-runs or under-runs the floor level when a stop is being made at a landing and for returning the car to the floor if a load getting on the car causes the cables to stretch sufiiciently to change the position of the car with reference to the floor while astop is being made. The leveling apparatus is old and well known in the art,

ill

and is here shown as represented by a down leveling switch S and an up leveling switch '1'. A down earn m and an up cam 'UC are provided for operating the levers E3 and T. The cams are so located that the lever B is operated by the Di} while the car is moving down to a position level. a floor and the cam Ur? so disposed as to operate the lever T when the car is moving up to a position level with the floor which a stop is being made. While the car level with the door, the levers are tree of the so that neither of the levers is operated while the car is in im floor level position. Nor molly, levers are held. in a retired position by a pair of retiring magnets SC and TC while the car is passing the various floors (not shown) but which release the levers to tail into their operating position tor leveling the car at a floor whenever the caris to stop at that floor.

The braking means for controlling the elevator includes a brake drum 20 mounted, on the shaft M in a position to be controlled by an electromagnetic brake 2i operated by a coil 22. The coil 22 is controlled by a brake relay M so connected in the circuit for the up and down direction switches that it will effect the energization or the brake coil 22 to release the brake 2! whenever either of the direction switches is energized for operating the car. 7

In accordance with my invention, it 'is desirable to ease the brake into braking position as softly and accurately as possible at the time the car is coming to a dead stop at a floor. A brake modifying relay K is provided for eflectlng this result through its control of the resistor RI.

Also, in accordance with my invention, the relay K is disposed to control, in cooperation with the brake relay M, a. generator strengthening relay l? which provides for the supply or more electrical energy to the generator when it is startine' in a leveling operation than it receives when starting to operate the car tor a run between floors. also, the brake H is provided with a pair or contact members BK which operate to place a resistor in circuit with the brake coil 22 when the brake reaches a predetermined posi tion, preferably when the brake is partially released.

It is believed that the invention may be best understood by an assumed operation oi the systern illustrated in the drawing.

have been closed to connect the supply conductors L+ and isto a suitable source; or supply or electrical energy. The energlzation or the supply conductors energizes the field winding it'll? or the motor ll? and prepares it for operation by the generator Q It will be assumed now that the car attendant moves the-car switch in a clockwise direction towards its on position to start the car downwardly. The operation of the car switch closes its contact members 30 and 3 l, thereby energizing the brake modifying relay K and the retiring magnet coils SC and TC. The energized relay K closes its contact members Kl, thereby short circuitlng the resistor Bl in the circuit to the brake cell it, thus preparing that coil i'or lull energize.-

tioro. The closing of. the contact members'Ki? Ill rection switch D and the brake relay M by a circuit extending from the supply conductor L+ through contact members 3!) and 32, coil D, contact members U4 and coil M to supply conductor L. The energized relay M closes its contact members Ml, thus energizing the brake coil 22 to release the brake 2!. The circuit for coil 22 extends i'rom supply conductor L-lthrough the contact members Kl, resistor R2, contact members BK, coil 22 and contact members Ml to supply conductor L. The relay M also closes con tact members M2, thereby energizing the genorator strengthening relay P which closes a selfholding circuit for itseli through members P3 and closes its members Pi and opens its contact members P2 to cause the generator field GP to be controlled through the resistors R4 and R5 in stead of through the resistor Rt, thereby preparing the generator to supply its normal amount of energy to the hoisting motor in starting to operate the car irom floor to floor.

The energized down direction switch D closes its contact members DI and D2 to energize the generator field GF to cause the generator G to supply suiilcient energy ior operating the hoistlng motor IS. The circuit for the field GF extends from supply conductor L+ through contact members D2, winding GF, contact members Di and PI and resistors R4 and R5 to the supply conductor L. The car now starts downwardly in operation with the brake fully released. As the brake moves to its fully released position, its arm engages and opens the switch BK. This places the resistor R3 in series with the coil 22, but inasmuch as the resistor BI is short; 'circuited by the contact members KI, and the coil 22 is fully energized, this does not now aflect the brake in any way, except to possibly reduce the amount oi current flowing through coil 22 while the car is running.

its the car attendant moves the switch CS still further, it closes its contact members 30 and 36, thereby energizing the intermediate speed relay it which thereupon closes its contact members it and thus short circuits the resistor R4 in the circuit oi the generator field to increase the speed or the car to its intermediate speed. As the attendaht moves the switch (38 still further, its contact members 30 and ill are closed, thereby energizing the high speed relay V which closes contact members Vl thereby short circuitlhg the resistor R5 in the generator ileld circuit and thus causing the car to operate downwardly at its lull speed.

It will be assumed now, that'the attendant,

desirous of stopping the car at the next iioor, moves the car switch CS toward its center position to efl'ect deceleration oi the car and cause it to stop at that floor. The opening of the contacts so and 31, and 30 and 36, deenergizes the high speed relay and intermediate speed relay to reinsert the resistors R5 and R1 in the generator :lleld circuit and thereby causes the car to de celerate to its stopping speed. As the car approaches near the floor landing during deceleration, the attendant moves car switch to its cen 'tral position thereby opening the contact urembers 39 and 32 at the time the lever S is opposite the cam DC. However, the opening of the contact members 30 and 32 does not deenergize the down direction switch D at this point because that switch is being maintained in energized position by reason of the fast that the lever S has its contact members S2 closed, thereby providing a self-holding circuit for the switch D which extends from the supply conductor L+ through the contact members S2 and D4, coil D, contact members U4 and coil M to supply conductor L.

As the car switch CS is centered, its contact members 30 and 3i are opened thereby deenergizing the relay K and the retiring magnets SC and TC. However, the leveling lever S now rests on its cam DC and its contact members 82 are still closed to maintain the circuit of the down direction switch D. The deenergized relay K opens its contact members Kl thereby reinserting the resistor RI in the circuit of the brake coil which reduces the excitation of that coil and prepares it to be softly and accurately applied when the car arrives at its stopping position. As the car continues towards its stopping position and arrives thereat, the lever S runs oil the lower end of the cam DC and is thereby operated to open its contact members S2 which deenergizes the down direction switch D to open its contact members Di and D2 and thereby deenergize the generator field winding GF. The opening of the contact members S2 also deenergizes the brake relay M which opens its contact members Mi, thus deenergizing the brake coil 22 and applying the brake to stop the car level with the floor. The deenergization of the relay M also opens its contact members M2 which return the generator strengthening relay P to its former deenergized condition in preparation for controlling the generator field in accordance with the generator to start in operation to move the car from fioorto floor or to move the car in a releveling operation. Hence it is seen that the use of the resistor RI and the control by the contact members Ki provides a means whereby the brake 2i may be softly and accurately applied at the last stage of deceleration of the car to a full stop at a floor.

It will be assumed now that a large number of passengers enter the car at the floor at which it is stopped and that this heavy load stretches the elevator cables sufliciently to lower the car to I a point below the point at which the leveling switches come into play automatically to return the car upwardly to its floor level. As the car moves downwardly under the weight of its load and the stretching of the cables, the lever T engages the cam U0 and is thereby operated to close its contact members T2. This energizes the up direction switch U by a circuit extending from supply conductor L+ through contact members T2 and Si, coil U, contact members DI and brake relay M to the supply conductor The energized relay M closes its contact members M2 without effect because the relay P cannot be.

energized until after relay K has been energized. However, the closing of the contact members Mi of the energized relay M energizes the brake coil 22 by a circuit extending from supply conductor L+ through the resistors RI and R2, the contact members BK, coil 22, and contact members MI to the supply conductor L-. The energized coil starts to release the brake 2| and when it is partially released the lever opens the contact members BK and thereby inserts resistor R3 in the circuit of the brake coil 22 to stop any further releasing movement of the brake. The resistors RI, R2 and R3 are now all in series with the coil 22 and,' therefore, that coil is energized only sufficiently to partially release the brake 2i.

The energization of the switch U at the time the brake relay M was energized closed the contact members Ui and U2, thereby energizing the generator field GF to operate the car upwardly.

This circuit extends from the supply conductor L+ to contact members Ui, field GF, contact members U2 and P2 and resistor R6 to the supply conductor L. It should be noted here that the resistor R6 is of less value than the resistors R4 and R5. Therefore, the generator will give the motor a greater amount of energy in this releveling operation than it would have been given if the car had started at its slowest speed in a run from one fioor to another floor. This increased energy for the motor will enable it to overcome the friction of the partially energized brake and pull the car back to a position level with the fioor. Hence it is seen that the system not only provides for maintaining a predetermined amount of braking friction on the car when it is leveled upwardly, but also at the same time provides for giving the hoisting motor a greater degree of power to enable it to pull through the partly applied brake. It will also be seen that this improvement of only partially releasing the brake when the car starts a releveling operation effects a much better result than fully releasing the brake in a releveling operation, because, when the brake is fully released and the generator is operated to level the car, the time required for the generator to build up in starting while the brake is fully released permits the car to move downwardly still further during this starting period. However, when the brake is only partially released for a releveling operation, the friction of the brake is sufilcient to prevent such additional downward drift of the car while the generator voltage is building up and yet is of such a' value that the generator with its increased power can overcome the friction of the brake and move the car back into its leveLwith-the-fioor position.

When the car completes its upward movement and returns to its position level with the floor, the lever T slides. on the upper end of the cam U0 and thereby opens itscontact members T2 and deenergizes the up direction switch U and the brake relay M. The deenergized switch U opens its contact members UI and U2, thus deenergizing the generator field GF, and the deenergized relay M opens its contact members Mi. thereby completely deenergizing the brake coil 22 and causing the brake 2| to be fully applied to stop and hold the car level with the floor. By reason of the foregoing operation, it will be and a generator control meanswhich will cause the car to come to a floor and stop level therewith by soft and accurate application of the brake. It will also be seen that if the car moves away from its level position at the floor either by reason of stretching of the cables due to a load or for any other reason, the system will keep the brake ,partially applied to the car and will supply the generator with suilicient force to move the car back to its floor level position even through the friction supplied by the partially applied brake.

The operation of the car in the up direction is essentially the same in the down direction, except that the car switch is moved in a contraclockwise direction for energizing the up direction switch instead of the down direction switch.

It will also be understood that my invention is equally applicable to a system in which the slow-down is accomplished automatically instead of by manual operationof a car switch.

Although I have illustrated and described only one specific embodiment of the invention, it is to be understood that many modifications thereof seen that I have provided a brake control means iii brake, means responsive to said one operation of the switch for connecting the circuit to efllect the release of the brake in starting and running the car, a resistor for said circuit, means respon sive to a predetermined releasing movement of said brake for rendering said resistor effective in said circuit, a second resistor for said circuit,

means responsive to said one operation of the switch for rendering said second resistor ineflective in said circuit while the car is starting and running at normal speed and responsive to operation of the switch to its off position for rendering said second resistor effective in said circuit during the last stages of deceleration of the car to prepare the brake for soft and accurate application in the stopping of the car, and means responsive to arrival of the car at the floor and to thefofl" position of the switch for opening the brake circuit to fully app the broke in stopping the -car. f

2. In an elevator system having a car serving a plurality of floors, apower means, a switch, means responsive to one operation of the switch for causing said power means to start the car and responsive to another operation of said switch for causing the power means to decelerate the car, an electromagnetic brake for-stopping the car, acircuit for the brake, means responsive torsaid one operation of the switch for connecting the circuit to effect the release 0! the brake in starting the car, leveling switches responsive to movement of the switch to its oflP' position and to overrun or underrun o! the car at a. floor at which it is to be stopped for effecting a leveling operation of the car at that floor, a resistor for the brake circuit, and a brake modifying relay responsive to operation of the switch towards its on" position for rendering said resistor ineffective while the car is starting and-running at normal speed and responsive to movement of the switch to its 05" position for rendering said resistor effective during the last stage of deceleration of the car to a stop and during operation of said leveling switches in leveling the car.

3. In an elevator system having a car serving a. plurality of floors, a power means, a-switch, means responsive to operation of the switch toward its on position for connecting the power means foroperating the car, a brake, means responsive to movement of the switch toward its "01? position for applying the brake tostop the car at a floor, a leveling means responsive to an underrun or an overrun of the car at a floor out which a stop is to he made for controlling the power means to return the car to a position op proximately level with the izioor and means re sponsive to operation of the leveling means for partially releasing the. brake leveling operation.

4. an elevator system car serving a plulolity of floors, a carver means, a switch, means responsive to op "ion of the switch to- -'s on position tor connecting the power mes s for operating the cor, a hralze means a second resistor in the brake circuit, and means brake torrendcring said second resistor eflective while the car is in the last stage of deceleration a'plurallty of floors, a power means, a switch,

I responsive to movement of the switch toward its "011 position for applying the brake to stop the car at a floor, a leveling means responsive to an underrun or an overrun oi the car at a floor at which a stop is being made for controlling the power means to return the car to a position approximately level with the floor, and means responsive to operation of the leveling means for partially releasing the brake. during the leveling operation and for controlling the power means to provide a greater degree or energy during the leveling operation than it provides during the initial starting of the car for a to another floor.

ii. In an elevator system having a car serving a plurality of floors, a. power means, a switch, means responsive to one operation of the switch for causing said power means to start the car and responsive to another operation of said switch for causing the power means to decelerate the car, an electromagnetic brake for stopping the car, a circuit for the brake, means responsive to said one operation 01 the switch for connecting the circuit to elect the release of the brake in starting the car, a resistor for said. circuit, means for effecting a leveling operation of the car at any floor at which a stop is being made,

a brake modiiying relay responsive to operation of the switch towards its on position for rendering said resistor ineffective while the car is starting and running at normal speed and responsive to movement of the switch to its 90!!" position for rendering said resistor effective during the last stage of deceleration of the car to a stop and during leveling operations of the car,

responsive to a predetermined movement of the anddurlng leveling operation of the car.

6. In an elevator system having acar serving means responsive to operation of the switch towards its on" position for connecting the power means for starting and running the car and responsive to operation of the switch toward its foif position for causing the power means to efiect deceleration of the car, an electromagnetic brake provided with a circuit, responsive toa decelerating operation of the switch and to arrival of the car at the floor to which the car is decelerating for applying the brake to hold the car level with the floor, a plurality of resistors in the brake circuit, means responsive to operation of the switch for rendering one or said resistors lnefiectlve during the running of the car and for rendering it elfectlve during the stopping and leveling operation of the car, and means responsive tomovement of the car away from a position level with the floor at which a stop is being made for controlling the power means to return the ear to a position approximately level with the floor and for connecting said brake circult through said first named resistor during the leveling operation to efiect s releasing movement of the hralre during said leveling operation,

means responsive to a predetermined movement of the brake toward its fully released position for ering effective av second resistor liar...-

whereby-e further releasing movement of the a pliwaiity oi? floors, a power means; a switch,

40 I connecting the power means circuit for startmeans responsive to operation of the switch towards its on position for connecting the power means for starting and running the car and responsive to operation of the switch towardits oif position for causing the power means to eifect deceleration of the car, an electromagnetic brake provided with a circuit, a leveling means responsive to decelerating operation of the switch and to arrival of the car to the floor for which the car is decelerating for applying the brake to hold the car level with the floor, a plurality of resistors in the brake circuit, means responsive to operation of the switch for rendering one of said resistors ineffective during the running of the car between floors and for rendering it effective during the stopping and leveling operation of the car, means responsive to a predetermined movement of the brake toward its full open position for rendering another of said resistors ineffective, and means responsive to operation of the leveling means for connecting said brake circuit through said first named resistor during the leveling operation to effect a releasing movement of the brake during said leveling operation and means responsive to a predetermined movement of the brake toward its fully released position for rendering a second resistor in the brake circuit eflective to prevent a further releasing movement of the brake to cause it to remain partially applied during the leveling operation, and means responsive to operation of the leveling means while the brake is partially applied for rendering the power means more powerful during the leveling operation than it was during the initial starting of the car for a run to another floor. 1

8. In an elevator system having a car serving a plurality of floors, a power means having l a circuit, a switch, means responsive to operation of the switch towards its "on position for ing and running the car and responsive to operation of the switch toward its of! position for controlling the power means circuit to effect deceleration oi the car, an electromagnetic brake provided with a circuit, a leveling means responsive to decelerating operation of the switch and to arrival of the car at theiioor to which it is deceieratingfor applying the brake to hold the car level with the floor, a plurality oi resistors in the brake circuit, means responsive to operation of the switch for rendering one of said resistors ineffective during the running of the car betweenfioors and for rendering it eil'ective during the stopping and leveling operation of the car, means responsive to a predetermined movement of the brake toward its full open position for rendering another of said resistors ineilfective, and means responsive to operation of the leveling means in releveling the car at a floor for connecting said brake circuit through said first named resistor during the releveling operation to efiect a releasing movement of the brake during said releveling operation, means responsive to a predetermined movement of the brake toward its fully released position for rendering a second resistor in the brake circuit effective to prevent a further releasing movement of the brake to cause the brake to remain partially applied during the releveling operation, a resistor for the power means circuit, means responsive to operation of the switch to start the car for controlling said power means resistor to control the acceleration and deceleration of the car in making a floor run, a second resistor for the power means circuit and means responsive to the operation of the leveling means in the releveling operation for rendering the second resistor of the power means effective and for rendering" the first resistor of the power means circuit ineffective during the leveling operation whereby the power means is given more power to pull the car through the partially applied brake in the releveling operation than it had in initially starting the car for a one-floor run.

9. In an elevator system having a car serving a plurality of floors, a power means, a switch, means responsive to operation of the switch toward its on" position for connecting the power means for operating the car, a brake, means responsive to movement of the switch toward its off position for applying the brake to stop the car at a floor, a leveling means responsive to an underrun or an overrun of the car at a floor at which a stop is being made for controlling the power means to return the car to a position approximately level with the floor, and means responsive to operation of the leveling means for applying the brake to retard movement of the car during the leveling operation and for applying energy to the power means to cause it to pull the car through the retarding eflect of the brake back to a level position with respect to the floor at which the car isto stop.

10. In an elevator system having a car serving a plurality 01' floors, a power means, a switch, means responsive to operation of the switch toward its on position for connecting the power means for operating the car, a brake, means responsive to movement of the switch toward its off position for applying the brake to stop the car at a floor, a leveling means responsive to an underrun or an overrun of the car at a floor at which a stop is being made for controlling the power means to return the car to a position approximately level with the floor, means responsive to operation of the leveling means for applying the brake to retard movementof the car during the leveling operation and for applying energy to the power means to cause it to pull the car through the retarding eiIect oi the brake back to a level position with respect to the floor at which the car is to stop, and means responsive to movement of the brake for controlling the retarding eflect of the brake to a predetermined degree during said leveling operation.

DANILO SAN'I'INI. 

